The present invention relates to surface cleaning extractors and wet vacuums. Such extractors are devices which apply a cleaning solution to a surface, such as carpet, upholstery and the like, and then vacuum the solution from the surface, extracting dirt and debris from the surface. Such extractors sometimes use built-in solution tanks and sometimes include attachment means with a long hose so the unit can obtain water from a faucet.
When a built-in solution tank is used, some means for pumping the solution from the tank to a cleaning tool is required. Such pumping function is typically accomplished by an electric pump which draws the solution from the tank and delivers it to the cleaning tool. Often times such pumps are expensive, self-priming units. Alternatively, such pumps can be non-self-priming and positioned such that gravity feeds the solution from the tank, to the pump for priming purposes. The pumping function can also be accomplished by pressurizing the solution tank and forcing, rather than drawing, the solution from the tank.
Both approaches are taught by Hurwitz in U.S. Pat. No. 4,123,818. Hurwitz discloses a closed pressure vessel or reservoir 10 which is pressurized via an air pump 28 for forcing the solution from the reservoir. Alternatively, a liquid pump assembly 128 is provided to drawn the solution from the tank. Inconsistent delivery of solution results from the use of the air pressurizing pump because the pressure within the reservoir decreases as solution leaves the reservoir. Further, subsequent pumping is required to repressurize the reservoir. Alternatively, the use of a liquid pump assembly adds cost and weight to the apparatus.
The various British and U.S. patents to Brazier (British Patents 2,038,168; 1,602,919: 1,602,918 and 1,601,456 and U.S. Pat. Nos. 4,287,636: 4,218,805 and 4,185,354) disclose a floor cleaning system in which the cleaning solution tank is pressurized by the extractor's suction fan exhaust. However, the pressure developed in the solution tank is back pressure to the suction fan and decreases the effective suction of the fan. Alternatively, a larger capacity suction fan assembly is required for a given level of suction when the exhaust is used to pressurize a solution tank for delivering solution to a cleaning tool. This results in a larger, more expensive and heavier suction fan assembly.
The commonly known home shop vacuum is typical of a wet vacuum. Such vacuums have the capability to vacuum liquid from a surface, but were not originally designed with a cleaning solution dispensing function. Accessory kits to add the cleaning solution dispensing function to wet vacuums are now becoming popular. A small solution tank is mounted on the cleaning wand and cleaning solution is drawn by gravity from the tank to the cleaning head for dispensing. Such a system has limitations. The cleaning solution tank is inherently small and limited in capacity, in turn limiting the size of the surface which can be cleaned for each filling of the cleaning solution tank and requiring frequent refillings to clean a room sized area. Also, the solution tank adds weight to the wand and diminishes its maneuverability.